91. Efflorescence is
- formation of white patches on the surface of bricks due to the presence of insoluble salts in the clay used for making bricks.
- swelling of bricks due to the presence of carbonaceous matter and gas.
- deformation arising due to exposure to the weather.
- presence of impurities in the clay used for making bricks that show up after burning.
92. The strength achieved by a brick depends on
- composition of brick earth
- nature of moulding adopted
- burning and cooling process
- all the above
93. What is the maximum allowable water absorption (%) of Indian burnt brick of class 2?